Making Things Talk

<?php

/*
        AIRNow Web Page Scraper
        Language: PHP
        Reads a web page and returns one line from it.
*/

// Define variables:
    // url of the page with the air quality index data for New York City:
    $url =
      'http://airnow.gov/index.cfm?action=airnow.showlocal&cityid=164'; 

    // open the file at the URL for reading:
    $filePath = fopen ($url, "r");

    // as long as you haven't reached the end of the file:
    while (!feof($filePath))
    {
        // read one line at a time, and strip all HTML and
        // PHP tags from the line:
        $line = fgetss($filePath, 4096);

        // if the previous line was the "observed at line" preceding
        // the particle matter reading, then $readParticles = 1 and
        // you should get this line, trim everything but the number,
        // and save the result in $particles:
        if ($readParticles == 1) {
            $particles = trim($line);
            echo "< AQI: $particles>";
            $readParticles = 0;
        }

        // if the current line contains the substring "AQI observed at"
        // then the line following it is either the particle reading
        // or the ozone reading:
        if (preg_match('/AQI observed at /', $line)) {
            // if $particles == -1, you haven't gotten
            // a value for it yet, so the next line
            // will be the particle value:
            if ($particles == -1) {
                $readParticles = 1;
            }
        }
    }
    // close the file at the URL, you're done:
    fclose($filePath);
?>